Hi Wilbur, I have 3 Japanese chisels now that I have set up more or less per instructions on the internet. One thing I can't figure out though is the reason that the back of the chisel should be flattened with a flat metal plate and polishing powder/compound vs just using a waterstone. I've used a waterstone for the initial flattening of the back. Am I missing something? Do you recommend I purchase a flat steel plate and powder for the backs of chisels? Thanks!
The downside of using a waterstone for the initial working the back of a chisel (or plane blade, for that matter) is that this is a task that is usually done by a coarser (less than 1000 grit) waterstone. Overall, coarser waterstones dish more quickly than finer grit waterstones, and so you run the risk of putting a slightly convex surface on the back of your chisel.
The flat steel plate and powder method has the advantage of the flat steel plate remaining, well, flat in use. The disadvantage is that it tends to be a messier process, since the powder tends to roll off the plate, and has to be refreshed every so often. Having said this, I should mention that I haven’t used this method very much, but I do have alternative ways of working the back of a chisel.
For me, if I need to flatten the back of a chisel or plane blade, if a 1000 grit waterstone isn’t working fast enough, I’ll use either my Atoma diamond plate that I use for flattening waterstones, or 80 grit Norton 3X sandpaper on a granite plate.
If you’re getting decent results with your waterstones, there’s no need to get the flat steel plate and powder. If you are not happy with the results you’re getting, then I would look into it.
Got my goose
Speaking of joinery, Neil Cronk started an interesting woodworking exercise on Twitter. Towards the end of March, Neil decided, for reasons that remain unknown to me, to take on cutting a lock rabbet miter joint, which is usually made with a router table, using hand tools instead. He live-tweeted this project, and it was fun to watch.
As a sequel, Neil decided to take on the lapped gooseneck joint, also known as a kamatsugi. In addition, Chris Wong, Adam Maxwell, and Shannon Rogers decided to join in. I decided to give this a try because someone needed to cut this joint with Japanese tools.
There are a number of variants of this joint. I decided to try making the mechigaihozotsuki kamatsugi, which is distinguished by incorporating a stub tenon in the lower half of the joint. This is a diagram of this joint, taken from The Complete Japanese Joinery. It was used for joining large beams end-to-end.
I started by milling up a 2x2 piece of walnut and crosscutting it. Each piece was laid out and marked separately. This was traditional practice. Although some of the lines could be marked together, many times it was not practical to line up large beams for this task. In fact, sometimes the layout was done by different people, relying on their skill to lay the lines out accurately.
I worked on making the male piece first. The first cut was made along the grain, defining the bottom face of the gooseneck and the top face of the half-lap. With this cut, I realized that the 210 mm ryoba that I usually use for joinery cuts was a bit small for 2x2 pieces, and switched to a 240 mm ryoba.
The next two cuts define the head of the gooseneck.
A vertical cut is made on the underside of the male piece. I knew at this point that I had already made my first mistake, which was cutting on the wrong side of the line.
Two shallow cuts are made to define the sloped back side of the goose head.
And a chisel was used to chop out the waste.
Some more saw cuts, chopping, and paring finish off the underside tenon.
This finished off the male piece. To make the female piece, I started by sawing waste off to provide the half-lap.
Sawcuts were made to define the neck, and more chiseling defined the mortise in the area of the head.
You can barely see a faint line on the side wall that is clearly not perpendicular, This is to mark the slope of the face of the female piece that matches up with the slope of the back of the goose head. I used the line as a guide to angle my chisel for paring. I don’t think achieving a perfect fit here is important. Like dovetails, the mechanical advantage will be there even if the fit isn’t perfect.
The last step was to make saw cuts and some chopping to define the mortise on the bottom of this piece. I forgot to take a picture of this part.
Then came fitting. This took up quite a bit of time, partially due to lack of experience on my part, and partially because I had to figure out which face of the joint to pare back to achieve a better fit. Finally, I was able to achieve this.
The male piece is not completely seated, but at this point the two pieces are wedged so closely together that this joint will stay this way for a very long time, even though there isn’t any glue in this joint.
After planing, though, it looked really good, for a first try.
The gap on the lower half reflects my sawing on the wrong side of that line early on in the process. It represents a two-saw kerf error. But overall, this joint came together surprisingly well, given that I didn’t mark one piece off of the other, and that I didn’t knife any of my lines before starting to cut them. Total time: about 30 minutes to mark the pieces, 1-1/2 hours for the making of the pieces, and 30 minutes of final fitting.
If you’re interested in seeing more, go to Twitter and look for #HandJoinery. This was a lot of fun.